AGFD 81

The objectives of this study were to select a good source of β-glucosidase among various kinds of plants, and to purify and characterize β-glucosidase from the selected natural product, Shiitake mushroom.

Seventeen natural products including Shiitake mushroom, almond, soybean group, and nut, were tested for beta-glucosidase activity. This enzyme was assayed by the modified procedure of Gunata et al. The crude enzyme was subjected to ammonium sulfate precipitation range of 30-90%. Dialyzed and concentrated enzyme solution was loaded on the two step anion-exchange (Resource Q) and gel filteration chromatography (Sephacryl S-100). The fractions with high protein concentration were collected and analyzed for β-glucosidase activity. Molecular weight was determined by SDS-PAGE.

Highly specific activity of β-glucosidase was in the order of Shiitake mushroom, almond, soybean group, and nut group, with range from 1.58 to 0.15 Unit/mg. Crude enzyme from Shiitake mushroom showed the highest β-glucosidase activity (1.65 Unit/mg) at 50-60% ammonium sulfate fraction. The elution profile obtained from two step chromatography revealed one kind of active peak, corresponding to a specific activity of 14.81 Unit/mg. The procedure described above resulted in 9.37-fold purification of β-glucosidase. The optimum pH and temperature for this enzyme were 7.0 and 60°C, respectively. And the molecular mass for the finally purified enzyme protein was estimated as the value of 38 kDa.

β-Glucosidase from Shiitake mushroom can be applied to cleave β-glucosidic linkages in phytochemicals and enhance the bioavailability.